The present invention relates to a toroidal continuously variable transmission, and more particularly to a gear housing for accommodating a gear train of the toroidal continuously variable transmission.
A so-called double cavity toroidal continuously variable transmission is known according to a publication "A Continuously Variable Transmission for Automotive Fuel Economy" SAE (Society of Automotive Engineers Inc.) Paper 751180, see FIG. 7 thereof.
U.S. Pat. No. 4,928,542 issued to Nakano on May 29, 1990 shows a double cavity toroidal continuously variable transmission. This transmission includes a gear train for transmitting a rotary motion of two output discs to an intermediate shaft. The gear train includes an output gear splined to both of the output discs, and a drive gear splined to the intermediate shaft. The output gear meshes the drive gear. The gear train is disposed between the output discs and supported by a gear housing which is also disposed between the output discs. The gear housing includes a first housing part fixedly secured to a transmission casing and a second housing part fixedly secured to the first housing part. The first and second housing parts extend to cover the opposite axial end faces of the output gear and are formed with bearing supports for the output gear. The first housing part extends further to cover one axial end face of the drive gear and is formed with a bearing support for the drive gear, but the second housing part does not further extend to cover the opposite axial end face of the drive gear. This structure of the gear housing is found to be not satisfactory in that it is difficult to sustain torque stress imparted to the drive gear, causing occurrence of gear noise between the output and drive gears.
An object of the present invention is to improve a toroidal continuously variable transmission such that occurrence of gear noise derived from a gear train is suppressed.